Relaxation-to-creep transition of domain-wall motion in a two-dimensional random-field Ising model with an ac driving field
Zhejiang University, Zhejiang Institute of Modern Physics - Hangzhou 310027, PRC
2 Asia Pacific Center for Theoretical Physics, POSTECH - Pohang 790-784, Korea
3 Center for Simulational Physics, The University of Georgia - Athens, GA 30602, USA
Accepted: 14 October 2010
Monte Carlo simulations of a two-dimensional, random-field Ising model with an ac driving field are used to study the relaxation-to-creep transition of domain-wall motion at low temperatures. The resultant complex susceptibility χ=χ′−iχ″ exhibits features in agreement with the experiments of ultrathin ferromagnetic and ferroelectric films: the semicircle and straight line in the χ′-χ″ plot are Cole-Cole signatures of relaxation and creep states, respectively. The exponent β describing the creep motion is measured, and an intermediate state between the relaxation and creep states is identified.
PACS: 64.60.Ht – Dynamic critical phenomena / 05.10.Ln – Monte Carlo methods / 75.60.Ch – Domain walls and domain structure
© EPLA, 2010